\FBMYSQLD_SAFE\FR

NAME

mysqld_safe - MySQL server startup script

SYNOPSIS

mysqld_safe options

DESCRIPTION

mysqld_safe

is the recommended way to start a
mysqld
server on Unix.
mysqld_safe
adds some safety features such as restarting the server when an error occurs and logging runtime information to an error log file. A description of error logging is given later in this section.

mysqld_safe
tries to start an executable named
mysqld. To override the default behavior and specify explicitly the name of the server you want to run, specify a
--mysqld
or
--mysqld-version
option to
mysqld_safe. You can also use
--ledir
to indicate the directory where
mysqld_safe
should look for the server.

Many of the options to
mysqld_safe
are the same as the options to
mysqld. See
Section 5.1.4, lqServer Command Optionsrq.

Options unknown to
mysqld_safe
are passed to
mysqld
if they are specified on the command line, but ignored if they are specified in the
[mysqld_safe]
group of an option file. See
Section 4.2.6, lqUsing Option Filesrq.

mysqld_safe
reads all options from the
[mysqld],
[server], and
[mysqld_safe]
sections in option files. For example, if you specify a
[mysqld]
section like this,
mysqld_safe
will find and use the
--log-error
option:

[mysqld]
log-error=error.log

For backward compatibility,
mysqld_safe
also reads
[safe_mysqld]
sections, but to be current you should rename such sections to
[mysqld_safe].

mysqld_safe
supports the following options. It also reads option files and supports the options for processing them described at
Section 4.2.7, lqCommand-Line Options that Affect Option-File Handlingrq.

*
--help

Display a help message and exit.

*
--basedir=dir_name

The path to the MySQL installation directory.

*
--core-file-size=size

The size of the core file that
mysqld
should be able to create. The option value is passed to
ulimit -c.

*
--datadir=dir_name

The path to the data directory.

*
--defaults-extra-file=file_name

Read this option file in addition to the usual option files. If the file does not exist or is otherwise inaccessible, the server will exit with an error.
file_name
is interpreted relative to the current directory if given as a relative path name rather than a full path name. This must be the first option on the command line if it is used.

For additional information about this option, see
Section 4.2.7, lqCommand-Line Options that Affect Option-File Handlingrq.

*
--defaults-file=file_name

Use only the given option file. If the file does not exist or is otherwise inaccessible, the server will exit with an error.
file_name
is interpreted relative to the current directory if given as a relative path name rather than a full path name. This must be the first option on the command line if it is used.

For additional information about this option, see
Section 4.2.7, lqCommand-Line Options that Affect Option-File Handlingrq.

*
--ledir=dir_name

If
mysqld_safe
cannot find the server, use this option to indicate the path name to the directory where the server is located.

As of MySQL 5.6.35, this option is accepted only on the command line, not in option files.

*
--log-error=file_name

Write the error log to the given file. See
Section 5.4.2, lqThe Error Logrq.

*
--malloc-lib=[lib_name]
The name of the library to use for memory allocation instead of the system
malloc()
library. As of MySQL 5.6.33, the option value must be one of the directories
/usr/lib,
/usr/lib64,
/usr/lib/i386-linux-gnu, or
/usr/lib/x86_64-linux-gnu. Prior to MySQL 5.6.33, any library can be used by specifying its path name, but there is a shortcut form to enable use of the
tcmalloc
library that is shipped with binary MySQL distributions for Linux in MySQL 5.6. It is possible that the shortcut form will not work under certain configurations, in which case you should specify a path name instead.

Note
As of MySQL 5.6.31, MySQL distributions no longer include a
tcmalloc
library.

The
--malloc-lib
option works by modifying the
LD_PRELOAD
environment value to affect dynamic linking to enable the loader to find the memory-allocation library when
mysqld
runs:

*
If the option is not given, or is given without a value (--malloc-lib=),
LD_PRELOAD
is not modified and no attempt is made to use
tcmalloc.

*
If the option is given as
--malloc-lib=tcmalloc,
mysqld_safe
looks for a
tcmalloc
library in
/usr/lib
and then in the MySQL
pkglibdir
location (for example,
/usr/local/mysql/lib
or whatever is appropriate). If
tmalloc
is found, its path name is added to the beginning of the
LD_PRELOAD
value for
mysqld. If
tcmalloc
is not found,
mysqld_safe
aborts with an error.

*
If the option is given as
--malloc-lib=/path/to/some/library, that full path is added to the beginning of the
LD_PRELOAD
value. If the full path points to a nonexistent or unreadable file,
mysqld_safe
aborts with an error.

*
For cases where
mysqld_safe
adds a path name to
LD_PRELOAD, it adds the path to the beginning of any existing value the variable already has.

Linux users can use the
libtcmalloc_minimal.so
included in binary packages by adding these lines to the
my.cnf
file:

[mysqld_safe]
malloc-lib=tcmalloc

Those lines also suffice for users on any platform who have installed a
tcmalloc
package in
/usr/lib. To use a specific
tcmalloc
library, specify its full path name. Example:

[mysqld_safe]
malloc-lib=/opt/lib/libtcmalloc_minimal.so

*
--mysqld=prog_name

The name of the server program (in the
ledir
directory) that you want to start. This option is needed if you use the MySQL binary distribution but have the data directory outside of the binary distribution. If
mysqld_safe
cannot find the server, use the
--ledir
option to indicate the path name to the directory where the server is located.

As of MySQL 5.6.33, this option is accepted only on the command line, not in option files.

*
--mysqld-version=suffix

This option is similar to the
--mysqld
option, but you specify only the suffix for the server program name. The base name is assumed to be
mysqld. For example, if you use
--mysqld-version=debug,
mysqld_safe
starts the
mysqld-debug
program in the
ledir
directory. If the argument to
--mysqld-version
is empty,
mysqld_safe
uses
mysqld
in the
ledir
directory.

As of MySQL 5.6.33, this option is accepted only on the command line, not in option files.

*
--nice=priority

Use the
nice
program to set the server's scheduling priority to the given value.

*
--no-defaults

Do not read any option files. If program startup fails due to reading unknown options from an option file,
--no-defaults
can be used to prevent them from being read. This must be the first option on the command line if it is used.

For additional information about this option, see
Section 4.2.7, lqCommand-Line Options that Affect Option-File Handlingrq.

*
--open-files-limit=count

The number of files that
mysqld
should be able to open. The option value is passed to
ulimit -n.

Note
You must start
mysqld_safe
as
root
for this to function properly.

*
--pid-file=file_name

The path name that
mysqld
should use for its process ID file.

*
--plugin-dir=dir_name

The path name of the plugin directory.

*
--port=port_num

The port number that the server should use when listening for TCP/IP connections. The port number must be 1024 or higher unless the server is started by the
root
system user.

*
--skip-kill-mysqld

Do not try to kill stray
mysqld
processes at startup. This option works only on Linux.

*
--socket=path

The Unix socket file that the server should use when listening for local connections.

*
--syslog,
--skip-syslog

--syslog
causes error messages to be sent to
syslog
on systems that support the
logger
program.
--skip-syslog
suppresses the use of
syslog; messages are written to an error log file.

When
syslog
is used, the
daemon.err
syslog facility/severity is used for all log messages.

*
--syslog-tag=tag

For logging to
syslog, messages from
mysqld_safe
and
mysqld
are written with identifiers of
mysqld_safe
and
mysqld, respectively. To specify a suffix for the identifiers, use
--syslog-tag=tag, which modifies the identifiers to be
mysqld_safe-tag
and
mysqld-tag.

*
--timezone=timezone

Set the
TZ
time zone environment variable to the given option value. Consult your operating system documentation for legal time zone specification formats.

*
--user={user_name|user_id}

Run the
mysqld
server as the user having the name
user_name
or the numeric user ID
user_id. (lqUserrq
in this context refers to a system login account, not a MySQL user listed in the grant tables.)

If you execute
mysqld_safe
with the
--defaults-file
or
--defaults-extra-file
option to name an option file, the option must be the first one given on the command line or the option file will not be used. For example, this command will not use the named option file:

mysql> mysqld_safe --port=port_num --defaults-file=file_name

Instead, use the following command:

mysql> mysqld_safe --defaults-file=file_name --port=port_num

The
mysqld_safe
script is written so that it normally can start a server that was installed from either a source or a binary distribution of MySQL, even though these types of distributions typically install the server in slightly different locations. (See
Section 2.1.4, lqInstallation Layoutsrq.)
mysqld_safe
expects one of the following conditions to be true:

*
The server and databases can be found relative to the working directory (the directory from which
mysqld_safe
is invoked). For binary distributions,
mysqld_safe
looks under its working directory for
bin
and
data
directories. For source distributions, it looks for
libexec
and
var
directories. This condition should be met if you execute
mysqld_safe
from your MySQL installation directory (for example,
/usr/local/mysql
for a binary distribution).

*
If the server and databases cannot be found relative to the working directory,
mysqld_safe
attempts to locate them by absolute path names. Typical locations are
/usr/local/libexec
and
/usr/local/var. The actual locations are determined from the values configured into the distribution at the time it was built. They should be correct if MySQL is installed in the location specified at configuration time.

Because
mysqld_safe
tries to find the server and databases relative to its own working directory, you can install a binary distribution of MySQL anywhere, as long as you run
mysqld_safe
from the MySQL installation directory:

shell> cd mysql_installation_directory
shell> bin/mysqld_safe &

If
mysqld_safe
fails, even when invoked from the MySQL installation directory, specify the
--ledir
and
--datadir
options to indicate the directories in which the server and databases are located on your system.

In MySQL 5.6.5 and later,
mysqld_safe
tries to use the
sleep
and
date
system utilities to determine how many times it has attempted to start this second, and---if these are present and this is greater than 5 times---is forced to wait 1 full second before starting again. This is intended to prevent excessive CPU usage in the event of repeated failures. (Bug #11761530, Bug #54035)

When you use
mysqld_safe
to start
mysqld,
mysqld_safe
arranges for error (and notice) messages from itself and from
mysqld
to go to the same destination.

There are several
mysqld_safe
options for controlling the destination of these messages:

*
--log-error=file_name: Write error messages to the named error file.

*
--syslog: Write error messages to
syslog
on systems that support the
logger
program.

*
--skip-syslog: Do not write error messages to
syslog. Messages are written to the default error log file (host_name.err
in the data directory), or to a named file if the
--log-error
option is given.

If none of these options is given, the default is
--skip-syslog.

If
--log-error
and
--syslog
are both given, a warning is issued and
--log-error
takes precedence.

When
mysqld_safe
writes a message, notices go to the logging destination (syslog
or the error log file) and
stdout. Errors go to the logging destination and
stderr.

COPYRIGHT

This documentation is free software; you can redistribute it and/or modify it only under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License.

This documentation is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with the program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see http://www.gnu.org/licenses/.

SEE ALSO

For more information, please refer to the MySQL Reference Manual,
which may already be installed locally and which is also available
online at http://dev.mysql.com/doc/.